1. Field of the Invention
The present invention relates to a method of transferring heat from one body to a second body. More particularly, the invention relates to a heat transfer device which employs a thermodynamic fluid for effecting heat transfer by expansion and compression of the thermodynamic fluid.
2. Description of the Prior Art
The basic principles of heat transfer in such systems as heat pumps and refrigerators is well known in which a thermodynamic fluid in a first body is allowed to expand by absorption of heat from the body followed by transfer of the expanded thermodynamic fluid to a second body where the expanded gas is compressed thereby liberating heat to the second body. A variety of gas or vaporous substances have been used as thermodynamic fluids in such heat transfer devices such as fluorocarbon based materials, ammonia, carbon dioxide and the like. While those thermodynamic fluids which are gas phase substances are usable over a wide range of temperature and pressure, they are generally less efficient and more awkward to practically operate than vapor phase thermodynamic fluids. On the other hand, thermodynamic fluids which are vapor phase substances are limited to rather narrow physical operating conditions and it is necessary to use different vapor materials, if in fact they can be obtained, for different and varying operating systems. A need therefore exists for a thermodynamic fluid which exhibits enhanced efficiency and/or more favorable operating characteristics in heat energies, heat pumps and refrigeration cycles.
A special type of heat transfer system, which has been commonly utilized in refrigeration systems, is one which utilizes the heat transfer effect achieved by the desorption of a gaseous substance such as hydrogen from a solid absorbent which requires heat in one body and absorption of the gas onto another sorbing solid in a second body which liberates heat. In such a system, the solid sorbents remain in their respective chambers while the desorbed gas is the working thermodynamic fluid. Van Mal et al in U.S. Pat. No. 4,111,002 show a cyclic desorption refrigerator and heat pump system which is based upon two thermodynamic units each of which is provided with two chambers each containing a solid metal alloy for the absorption of hydrogen, which is the working thermodynamic gas. Prost et al in U.S. Pat. No. 3,704,600 show a cryogenic refrigerator which is based upon hydrogen as the working thermodynamic gas. The device contains two working chambers each of which contains a metal alloy which absorbs hydrogen. Heat is transferred in the device by heating the solid in one chamber thereby desorbing hydrogen from the same and creating a high pressure hydrogen gas which flows through counter flow heatexchangers and is throttled. The cooled throttled gas flows through the place to be cooled and then is eventually absorbed in the other cooled working chamber. Other prior art references which disclose heat transfer systems based upon the desorption and absorption of a working thermodynamic gas are U.S. Pat. Nos. 3,397,549 and 3,854,301.